Resistance of aggregate to wear in the Los Angeles machine (IS 2386 Part 4).
Sieve Analysis (Aggregate)Impact ValueCrushing ValueSpecific Gravity & Absorption
Aggregate Abrasion Value (Los Angeles) Calculator: Free Online Tool
The Los Angeles abrasion value tells you how well a coarse aggregate resists wear and impact. A sample is tumbled in a steel drum with steel balls, then sieved. The share of material broken down to fines is the abrasion value, so a lower number means a tougher stone.
This calculator works out the value from your original dry mass and the dry mass retained on the 1.70 mm sieve. Aggregate suppliers, site engineers and lab technicians use it to accept or reject stone for road surfaces, concrete and pavement layers. Doing the arithmetic correctly matters, because a small error in mass can move the result across the specification limit and change a purchase decision. The tool works in feet and inches or in metres and millimetres, so it suits both older site practice and metric drawings, and every result can be rechecked by hand.
When to use this calculator
Use this calculator whenever you have finished a Los Angeles machine test and need the abrasion value quickly. It suits quarry quality checks, incoming stone checks at a batching plant or road site, and routine work in a materials laboratory. Students can also use it to verify hand calculations for a lab report. Because it takes two trials, you can compare repeat tests on the same sample and see their average. It is also helpful when you want to compare stone from different quarries before approving a source for a project.
How to use the Aggregate Abrasion Value (Los Angeles) Calculator
- Open the calculator above on your phone, tablet or computer. Nothing needs to be installed and no sign-up is required.
- Enter your values in the input boxes: Original mass A (g), Retained on 1.70 mm B (g). The boxes already hold sample values, so overwrite them with your own.
- Press Calculate. The result appears straight away under the button.
- Change any value and press Calculate again to compare options. Press Reset to go back to the sample values.
- Check the result against your drawings, project specification and local code before you order material or approve work.
How the calculation works
For each trial the calculator applies: Abrasion value = (A - B) / A x 100. A is the original oven-dry mass of the sample and B is the dry mass retained on the 1.70 mm sieve after the test, washed and oven-dried. Both are entered in grams. The default sample is 5,000 g, which is about the standard sample for Grading A. With the defaults (B = 3,850 g and 3,880 g) the trials give 23.00 % and 22.40 %, averaging 22.70 %. Leave a trial blank to skip it. The result is then compared with an IS 383 limit shown in the calculator, for example 30 % for wearing surfaces.
Worked example
When you open the page the calculator is filled with sample values. Pressing Calculate with those values gives the result below, which you can use to check that you are reading the output correctly.
| Result of each trial | |
|---|---|
| Trial 1 (mass worn away 1,150 g) | 23.00 % |
| Trial 2 (mass worn away 1,120 g) | 22.40 % |
| Result | |
| Los Angeles abrasion value | 22.70 % |
| Check against IS 383 limit | |
| Wearing surfaces (limit 30 %) | Within limit |
Tips and common mistakes
- Wash the retained material on the 1.70 mm sieve and oven-dry it fully before weighing, otherwise water mass makes B too high and the value too low.
- Enter A as the actual dry mass of the charge you placed in the drum, not the nominal 5 kg, so the percentage is correct.
- Check that both trials are close to each other. A large gap between trials usually points to a weighing mistake or a non-uniform sample.
- Use the grading, ball charge and revolutions given in your test standard. This calculator only does the arithmetic and cannot confirm the test was run correctly.
- Compare the result with the limit in your project specification for the intended use, since the limit differs between wearing surfaces and other layers.
Frequently asked questions
What does a lower Los Angeles abrasion value mean?
A lower value means less material broke down into fines during the test, so the aggregate is harder and more resistant to wear. A higher value means the stone is weaker and may crush or wear quickly under traffic.
Which sieve is used to find the retained mass B?
The calculator uses the 1.70 mm sieve. After the test the sample is washed over this sieve, and the material retained is oven-dried and weighed. This dry mass is entered as B in grams.
Why does the calculator accept two trials?
Two trials let you see how repeatable the test is. The calculator shows the abrasion value of each trial and then their average. If you only ran one test, leave the second trial blank and it will be skipped.
What limit does the calculator compare against?
It compares the average value with the IS 383 limit stated in the result, which is 30 % for wearing surfaces. Your project specification may set a different limit, so always confirm it before accepting aggregate.
Does the sample size have to be 5,000 g?
No. The formula uses a percentage, so any original mass works. The default of 5,000 g reflects the usual sample for Grading A. Use the mass your test method requires for the grading you tested.
Important note
This tool gives estimates for planning, study and quick checks. It does not replace design by a qualified engineer, site-specific testing, or the requirements of your project specification and local building code. Always confirm final quantities, test results and acceptance limits with the responsible engineer before using them for construction or payment.
